This ATLAS O TRAINMAN® model is based upon the typical RBL class of insulated box cars that were used to carry canned goods that required protection from extremes of temperature, but not refrigeration. These cars had neither ice bunkers nor cooling units.
Plug-style doors were normally used to ensure a tight seal in the insulation. Designed for transport of both perishables and large loads, plug doors allowed box cars to be sealed from outside dust and dirt.